Rotary hook for sewing machines



Jan. 9, 1962 BONO 3,016,032

ROTARY HOOK FOR SEWING MACHINES Filed March 18, 1958 2 Sheets-Sheet 1 9FIG.

V INVENTOR.

Jan; 9, 1962 L. BONO 3,016,032

ROTARY HOOK FOR SEWING MACHINES Filed March 18. 1958 2 Sheets-Sheet 2FIG. 2

INVENTOR.

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j /fl r 7 United States Patent 3,016,032 Patented Jan. 9, 1962 3,616,032ROTARY HGGK FGR SEWING MACHINES Luigi Bono, Pavia, Milan, Italy,assignor to Necchi S.p.A., Pavia, italy filed Mar. 18, 1953, Ser. No.722,167 Claims priority, application Italy Mar. 28, 1957 9 Claims. (Cl.112236} This invention refers to a rotary hook for two threaded,lockstitch sewing machines. The purpose is to introduce a fewimprovements to the parts connecting the retaining ring of the bobbincase holder to the rotary hook body.

In accordance with the present invention, a movable bobbin holder deviceis connected to the hook body by means of a movable coaxial lockingdevice with that body which can be turned on a common axis so that thedisengagement of the parts is obtained by means of rotation.

in order that the present invention may be readily carried into effect,it will now be described with reference to the accompanying drawing,wherein:

FIG. 1 shows an axial section, along a line II (FIG. 3) of the rotarybody;

FIG. 2 shows the single parts of the rotary hook in perspective,according to the way they are assembled;

FIG. 3 is a back View of the hook in the normal sewing position;

FIG. 4 shows the same back view after the disengagement has taken place;and

FIG. 5 illustrates the rotary hook fitted into the sewing machine.

The rotary body indicated as 1 and provided with a catching hook 2, isfixed by means of screws 4 on shaft 3, the latter continuously rotating,as is commonly known and therefore not illustrated.

The rotary body is provided with a circular guide 5 which is partlyclosed by the retaining ring 6 of the bobbin case holder 8 so as to forma groove which will house the circular rib 7 of the bobbin case holder8. Inside the bobbin case holder there is, as usual, an axial pivot 9onto which the bobbin case 9 (FIG. 5) will be slipped.

It must be understood that, without drifting away from the subject, thecatching hook 2, instead of being part of the body 1, could be an end ofthe retaining ring 6. The retaining ring 6 has two small axial pins 19and 11 which match the two grooves 12 and 13 of the hook body 1. Thesepins have two notches 14 and 15, respectively, designed to receive thelocking device.

The locking device is formed by the two blades 16 and 17 of the elasticplate 18 fixed to the knurled locking ring 19, This locking ring isfitted to the hook body hub 1 and can rotate but its rotation is limitedby a pivot 29 (FIGS. 3 and 4) connected to the hook body 1 and whichextends into the slot 21 on locking ring 19. The locking ring 19 isaxially held by retainer 22 by means of washer 23 which providesfriction for the locking ring rotation.

When the hook is in normal sewing position, as in FIGS. 1 and 3, theelastic blades 16 and 17 of the plate 18 will engage in notches and 14of the small pins 16 and 11, exerting an axial load on them in thedirection indicated by the arrows A (FIG. 1), thus efiecting the exactpositioning and connecting of the retaining ring 6 to the hook body 1; aslight elasticity between the two parts will prove very useful when dirtor pieces of thread are caught in between. The disengagement of theretaining ring 6 for the ex traction of the bobbin case holder 8 isobtained by rotating the locking ring 19 in the direction indicated bythe arrow a (FIG. 3) while shaft 3 is held steady by the other parts ofthe sewing machine. The locking ring 19 has been provided with mappropriate knurled border 24 to facilitate rotation.

Once the rotation has been effected (FIG. 4), the small pins 19 and 11will be disengaged from the blades 16 and 17 so that the retaining ring6 can be easily extracted. When the retaining ring 6 and the bobbin caseholder 8 have been removed for cleaning of the circular guide 5, thelocking ring 19 will remain in the position indicated in H6. 4, becausethe elastic washer 23 exerts sufilcient friction between the surfaces incontact of the locking ring 19 and the hook body 1, to avoid areciprocal rotation of the two parts. This is useful for thereassembling of retaining ring 6. For this operation the bobbin caseholder 8 must be inserted with its rib 7 resting on guide 5, then theretaining ring 6 must be reassembled by inserting the two small pins 10and 11 respectively into the two grooves 12 and 13.

The hook is then positioned as illustrated in FIG. 4. To fix it in thatposition, the locking ring 19 must be rotated in the direction indicatedby the arrow b until it is in the position shown in FIG. 3.

As is well known, the bobbin case holder 8 is held in a fixed positionby means of the retainer 25 (FIG. 5) corresponding to the slot 26 on thebobbin case holder 8.

The retainer 25 is a part of the piece 27 fixed on the lower part of theneedle plate 28 (FIG. 5). Therefore, when pieces of thread or dirt getstuck between the rib 7 and the guide formed by parts 5 and 6, causingthe rotary body to jam in respect of the bobbin case holder 8, thedisengaging device of the parts, formed by the locking ring 19 that canbe rotated, is particularly handy because it is always possible to moveit in whatever position it stops. if the dismantling were to be obtainedby moving two pieces situated in determined positions around the rotarybody, there would always be the risk of their stopping near the needleplate or near the retainer 25 of the bobbin case holder 8 and the smallspace available would make it impossible to move them.

As mentioned, the locking devices are sprung (elastic blades 16-17) sothat in the case of lint or dirt getting caught, the retaining ring 6 ofthe bobbin case holder 8 can move slightly away along its axis, from therotary body thus avoiding sudden jamming and consequent seriousinconveniences in the running of the machine. Moreover, the blades 16and 17 are slanted in respect to the perpendicular plane of the rotationaxis so that the locking motion determines an elastic deformation of theblades and consequently an axial locking load between the parts 1 and 6.

Without further analysis, the foregoing will so fully reveal the gist ofthe present invention that others can by applying current knowledgereadily adapt it for vari 0113 applications without omitting featuresthat, from the standpoint of prior art, fairly constitute essentialcharacteristics of the generic or specific aspects of this inventionand, therefore, such adaptations should and are intended to becomprehended within the meaning. and range of equivalence of thefollowing claims.

What is claimed as new and desired to be secured by Letters Patent is:

I claim:

1. A rotary hook for sewing machines comprising, in combination, rotarybody means having an axis; retaining means non-rotatably mounted on saidbody means and abutting said body means in axial direction for retaininga bobbin holder in said body means; a locking member mounted on saidbody means for turning movement about said axis: and locking meanscomprising a first operative engaging component on said retaining meansand a second operative engaging component on said locking me her, saidfirst and second operative engaging components being positioned whensaid locking member is turned in one direction to engage in lockingcontact to lock said retaining means to said body means and when saidlocking member is turned in the opposite direction to disengage fromlocking contact to release said retaining means from said body means topermit movement of said retaining means in the axial direction of saidbody means for removal of said retaining means.

2. A rotary hook for sewing machines co-mrising, in combination, rotarybody means having an axis; retaining means non-rotatably mounted on saidbody means and abutting said body means in axial direction for retaininga bobbin holder in said body means; a locking member mounted on saidbody means for turning movement about said axis; and locking meanscomprising a first operative engaging component on said retaining meansand a second operative engaging component on said locking member, saidfirst and second operative engaging components being positioned whensaid locking member is turned in one direction to engage in lockingcontact to lock said retaining means to said body means and when saidlooking member is turned in the opposite direction to disengage fromlooking contact to release said retaining means from said body means topermit movement of said retaining means in the axial direction of saidbody means for removal of said retaining means; and resilient meanssecured to said body means and abutting said locking member andfrictionally engaging the latter so as to permit turning movement ofsaid locking member while frictionally holding said locking member inthe locking and releasing positions. I

3. -A rotary hook for sewing machines comprising, in combination, rotarybody means having an axis; retaining means non-rotatably mounted on saidbody means and abutting said body means in axial direction for retaininga bobbin holder in said body means; a locking member mounted on saidbody means for turning movement about said axis, said locking memberincluding a manually turnable ring; and locking means comprising a firstoperative engaging component on said retaining means and a. secondoperative engaging component on said looking member, said secondoperative engaging component comprising resilient blade means secured tosaid ring and extending transverse to said axial direction so as to beresilient in said axial direction, said first and second operativeengaging components being positioned when said locking member is turnedin one direction to engage in locking contact to lock said retainingmeans to said body means and when said locking member is turned in theopposite direction to disengage from locking contact to release saidretaining means from said body means totpermit movement of saidretaining means in the axial direction of said body means for removal ofsaid retaining means. 7

4. A rotary hook for sewing machines comprising, in combination, rotarybody means having an axis; retaining means non-rotatably mounted on saidbody means and abutting said body means in axial direction for retaininga bobbin holder in said body means; a locking member mounted on saidbody means for turning movement about said axis, said locking memberincluding a manually turnable ring; and locking means comprising a firstoperative engaging component on said retaining means and a secondoperative engaging component on said locking member, said secondoperative engaging component comprising resilient blade means secured tosaid ring and extending transverse to said axial direction so as to beresilient in said axial direction, said first and second operativeengaging components being positioned when said locking member is turnedin one direction to engage in locking contact to lock said retainingmeans to said body means and when said locking member is turned in theopposite direction to disengage from locking contact to release saidretaining means from said body means to permit movement of saidretaining means in the axial direction of said body means for removal ofsaid retaining means and resilient means secured to said body means andabutting said locking member and fric tionally engaging the latter so asto permit turning movement of said locking member while frictionallyholding said locking member in the locking and releasing positions. t

5. A rotary hook for sewing machines comprising, in combination, rotarybody means having an axis; retaining means non-rotatably'mounted on saidbody means and abutting said body means in axial-direction for retaininga bobbin holder in said body means; a locking member mounted on saidbody means for turning movement about said axis, said locking memberincluding a manually turnable ring and a portion radially projectingfrom said rotary body means so as to'be adapted to be manually grippedfor turning said locking member; and locking means comprising a firstoperative engaging component on said retaining means and a secondoperative engaging component on said locking member, said secondoperative engaging component comprising resilient blade means secured tosaid ring and extending transverse to said axial direction so as to beresilient in said axial direction, said first and second operativeengaging components being positioned when said locking member is turnedin one direction to engage in locking contact to lock said retainingmeans to said body means and when said locking member is turned in theopposite direction to disengage from locking contact to release saidretaining means from said body means to permit movement of saidretaining means in the axial direction of said body means for removal ofsaid retaining means and resilient means secured to said body means andabutting said locking member and frictionally engaging the latter so asto permit turning movement of said looking member while frictionallyholding said locking member in the iocking and releasing positions. a

6. A rotary hook for sewing machines comprising, in combination, rotarybody means having an axis; retaining means non-rotatably mounted on saidbody means and abutting said body means in axial direction for retaininga bobbin holder in said body means; locking member mounted on said bodymeans for turning movement about said axis, said locking memberincluding a manually turnable ring; and locking means comprising a firstoperative engaging component on said retaining means and a secondoperative engaging component on said locking member, said secondoperative engaging component comprising resilient blade means secured tosaid ring and extending transverse to said axial direction so as to beresilient in said axial direction, said first and second operativeengaging components being positioned when said locking member is turnedin one direction to engage in locking contact to lock said retainingmeans to said body means and when said locking member is turned in theopposite direction to disengage from locking contact to release saidretaining means from said body means to permit movement of saidretaining means in the axial direction of said body means for removal ofsaid retaining means, said blade means being slanted to the axialdirection of said body means so that the resilient locking pressure ofsaid blade means on said retaining means increases during turningmovement of said locking member toward the locking position.

7. A rotary hook for sewing machines comprising, in combination, rotarybody means having an axis; retaining means non-rotatably mounted on saidbody means including a retaining ring for retaining a bobbin holder insaid body means, said retaining ring abutting said body means in axialdirection; a locking member mounted on said body means for turningmovement about said axis, said locking member including a manuallyturnable ring; and locking means comprisinga first operative engagingcomponent on said retaining means and a second operative engagingcomponent on said locking member, said first operative componentcomprising a pin fixedly secured to said retaining ring and extending insaid axial direction, said pin engaging a matching portion of said bodymeans to prevent turning of said retaining ring relative to said bodymeans, said pin having at the free end thereof a cutout, said secondoperative engaging component comprising resilient blade means secured tosaid manually turnable ring and extending transverse to said axialdirection so as to be resilient in said axial direction, said first andsecond operative engaging components being positioned when said lockingmember is turned in one direction to engage in locking contact whereinsaid blade means engages said cutout to lock said retaining means tosaid body means and when said locking member is turned in the oppositedirection to disengage from looking contact wherein said blade meansdisengages from said cutout to release said retaining means from saidbody means to permit movement of said retaining means in the axialdirection of said body means for removal of said retaining means.

8. A rotary hook for sewing machines comprising, in combination, rotarybody means having an axis; retaining means non-rotatably mounted on saidbody means including a retaining ring for retaining a bobbin holder insaid body means, said retaining ring abutting said body means in axialdirection; a locking member mounted on said body means for turningmovement about said axis, said locking member including a manuallyturnable ring; and locking means comprising a first operative engagingcomponent on said retaining means and a second operative engagingcomponent on said locking member, said first operative componentcomprising a pair of pins fixedly secured to said retaining ring andextending in said axial direction, each of said pins engaging matchingportions of said body means to prevent turning of said retaining ringrelative to said body means, each of said pins having at the free endthereof a cutout, said second operative engaging component comprisingresilient blade means secured to said manually turnable ring andextending transverse to said axial direction so as to be resilient insaid axial direction, said first and second operative engagingcomponents being positioned when said locking member is turned in onedirection to engage in locking contact wherein said blade means engagessaid cutouts to lock said retaining means to said body means and whensaid locking member is turned in the opposite direction to disengagefrom locking contact wherein said blade means disengages from saidcutouts to release said retaining means from said body means to permitmovement of said retaining means in the axial direction of said bodymeans for removal of said retaining means, said blade means beingslanted to the axial direction of said body means so that the resilientlocking pressure of said blade means on said retaining means increasesduring turning movement of said locking member toward the lockingposition.

9. A rotary hook for sewing machines comprising, in combination, rotarybody means having an axis; retaining means non-rotatably mounted on saidbody means including a retaining ring for retaining a bobbin holder insaid body means, said retaining ring abutting said body means in axialdirection; a locking member mount ed on said body means for turningmovement about said axis, said locking member including a manuallyturnable ring having a knurled surface to facilitate manual operation;and locking means comprising a first operative engaging component onsaid retaining means and a second operative engaging component on saidlocking member, said first operative component comprising a pair of pinsfixedly secured to said retaining ring in diametrically opposedpositions and extending in said axial direction, each of said pinsengaging matching portions of said body means to prevent turning of saidretaining ring relative to said body means, each of said pins having atthe free end thereof a cutout, said second operative engaging componentcomprising resilient blade means secured to said manually turnable ringand extending transverse to said axial direction so as to be resilientin said axial direction, said first and second operative engagingcomponents being positioned when said locking member is turned in onedirection to engage in locking contact wherein said blade means engagessaid cutouts to lock said retaining means to said body means and whensaid locking member is turned in the opposite direction to disengagefrom locking contact wherein said blade means discngages from saidcutouts to release said retaining means from said body means to permitmovement of said retaining means in the axial direction of said bodymeans for removal of said retaining means, said blade means beingslanted to the axial direction of said body means so that the resilientlocking pressure of said blade means on said retaining means increasesduring turning movement of said locking member toward the lockingposition.

